Is the glass half empty or half full?

A prospective study of optimism and coronary heart disease in the normative aging study
Laura D. Kubzensky, David Sparrow, Pantel Vokonas and Ichiro Kawachi
Harvard School of Public Health; Harvard medical School; Department of Veterans Affairs Outpatient Clinic; Boston University School of Medicine

Published in 'Psychosomatic Medicine', 63, 910-916, 2001

This study examined the relationship between an optimistic or pessimistic explanatory style and the incidence of coronary heart disease in a sample of older men (average age 61 years). In 1986, 1306 men completed a personality inventory that included measures of optimism and pessimism. People with an optimistic explanatory style are likely to consider negative events as being caused by external, transient, and specific causes, whereas, individuals with a pessimistic explanatory style tend to blame themselves and to explain bad events as being caused by chronic factors that can generalise to other situations. After completing the personality questionnaire, participants were monitored over a period of 10 years and were given medical examinations to measure coronary risk factors.

162 participants developed coronary heart disease over the 10-year follow-up period and the findings indicated that men with a more optimistic explanatory style had a lower risk of coronary heart disease. The protective effect appeared to be independent of health damaging behaviours, such as smoking and alcohol consumption. The relationship also persisted when high levels of anxiety, anger, or depression were excluded or controlled, as these emotions may increase the risk of coronary heart disease. This indicated that optimism and pessimism are independent of negative emotions. However, there was no association between an optimistic explanatory style and mortality.

The researchers suggest that explanatory style may influence the degree of stress to which individuals are exposed. For example, optimistic individuals may engage in more planning and problem solving that reduces their stress levels and that this may contribute towards a reduced risk of coronary heart disease. They may also have more psychological resources to deal with stress, as they perceive events in a more positive light compared to pessimistic individuals and therefore experience more positive emotions that have an effect on their general health and well-being.

The researchers also highlighted the limitations of the findings, as the study was based on data collected from white men and therefore cannot be generalised to women or to non-white populations. Furthermore, they found that individuals with less education were more likely to be pessimistic and suggested that environmental factors, such as poverty, unemployment, or work stress, may decrease the likelihood of optimism, thus increasing the risk of coronary heart disease. It was therefore emphasised that further research should consider whether or not optimism has the capacity to buffer the effects of poor social environments.